Dispersion and gain in generic slow-wave structures

Two devices: the dielectric-lined waveguide or Cerenkov maser and the metal grating based planar protron, have been operational for several years. Recently a segmented grating resonator, the planar-grating klystron, has also been introduced. The grating in the protrons and the dielectric in the Cerenkov device serve as slow-wave structures which guide electromagnetic radiation and couple it to an electron beam. The frequency and output power of the radiation produced depend upon the characteristics of both the beam and the slow-wave structure. A generic theory which is capable of predicting the tuning, gain, saturation, relative efficiency and sensitivity to electron beam quality has been developed. An introduction to the theory and a summary of some recent applications are discussed